oil leak on valve cover

[MustangFTW]

Hey guys,

I have an 03 Mazda6 and I've had to keep refilling the oil, about 2 quarts every month. Finally I got time to check it out and I noticed a lot of old burnt oil on top of the valve cover, around the spark plugs boots, I had a shop replace the valve cover since they owed me a favor and after getting to work I popped the hood and noticed a small pool of oil around the same spots.

I'm at work so I can't check right now but I plan on checking the valve cover bolts when I get home, hoping they just didn't tighten them properly...

Any other ideas?